For example, as a surface decorative material of a decorative panel or a decorative top plate used in an interior of a railroad vehicle, an automobile, a ship, or the like, various materials such as different kinds of sheet bonding materials such as a vinyl chloride decorative sheet; an FRP molded article; a designable stainless steel plate; a composite material of a metal plate and a resin foam; a coated metal plate; and a melamine resin decorative sheet are generally used. Among these decorative materials, the melamine resin decorative sheet in particular is widely used as an interior material, particularly for a decorative surface of a vehicle or a ship as a material which has a hard surface, excellent heat resistance and contamination resistance, and high durability (maintenance of a beautiful appearance).